What is the role of electrophysiologic testing in the workup of carpal tunnel syndrome (CTS)?

Updated: Mar 30, 2020
  • Author: Nigel L Ashworth, MBChB, MSc, FRCPC; Chief Editor: Milton J Klein, DO, MBA  more...
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Electrophysiologic testing also can provide an accurate assessment of how severe the damage to the nerve is, thereby directing management and providing objective criteria for the determination of prognosis. CTS is usually divided into mild, moderate, and severe; however, criteria for this assessment usually vary from lab to lab. In general, patients with mild CTS have sensory abnormalities alone on electrophysiologic testing, and patients with sensory plus motor abnormalities have moderate CTS. However, any evidence of axonal loss (eg, decreased or absent sensory or motor responses distal to the carpal tunnel or neuropathic abnormalities on needle EMG) is classified as severe CTS.

Changes in electrophysiologic results over time can be used to assess the success of various treatment modalities.

The American Association of Electrodiagnostic Medicine has published standards and guidelines that govern the minimum number of studies that should be performed to diagnose CTS. [4]

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